Commit f6cde920 authored by Yu Zhang's avatar Yu Zhang Committed by Sean Christopherson
Browse files

KVM: nVMX: Add helpers to setup VMX control msr configs 



nested_vmx_setup_ctls_msrs() is used to set up the various VMX MSR
controls for nested VMX. But it is a bit lengthy, just add helpers
to setup the configuration of VMX MSRs.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarYu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230119141946.585610-2-yu.c.zhang@linux.intel.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent ad36aab3

arch/x86/kvm/vmx/nested.c

+74 −33
Original line number Diff line number Diff line
@@ -6753,36 +6753,9 @@ static u64 nested_vmx_calc_vmcs_enum_msr(void) 
	return (u64)max_idx << VMCS_FIELD_INDEX_SHIFT;

}



/*

 * nested_vmx_setup_ctls_msrs() sets up variables containing the values to be

 * returned for the various VMX controls MSRs when nested VMX is enabled.

 * The same values should also be used to verify that vmcs12 control fields are

 * valid during nested entry from L1 to L2.

 * Each of these control msrs has a low and high 32-bit half: A low bit is on

 * if the corresponding bit in the (32-bit) control field *must* be on, and a

 * bit in the high half is on if the corresponding bit in the control field

 * may be on. See also vmx_control_verify().

 */

void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

static void nested_vmx_setup_pinbased_ctls(struct vmcs_config *vmcs_conf,

					   struct nested_vmx_msrs *msrs)

{

	struct nested_vmx_msrs *msrs = &vmcs_conf->nested;



	/*

	 * Note that as a general rule, the high half of the MSRs (bits in

	 * the control fields which may be 1) should be initialized by the

	 * intersection of the underlying hardware's MSR (i.e., features which

	 * can be supported) and the list of features we want to expose -

	 * because they are known to be properly supported in our code.

	 * Also, usually, the low half of the MSRs (bits which must be 1) can

	 * be set to 0, meaning that L1 may turn off any of these bits. The

	 * reason is that if one of these bits is necessary, it will appear

	 * in vmcs01 and prepare_vmcs02, when it bitwise-or's the control

	 * fields of vmcs01 and vmcs02, will turn these bits off - and

	 * nested_vmx_l1_wants_exit() will not pass related exits to L1.

	 * These rules have exceptions below.

	 */



	/* pin-based controls */

	msrs->pinbased_ctls_low =

		PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR;
@@ -6795,8 +6768,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 
	msrs->pinbased_ctls_high |=

		PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR |

		PIN_BASED_VMX_PREEMPTION_TIMER;

}



	/* exit controls */

static void nested_vmx_setup_exit_ctls(struct vmcs_config *vmcs_conf,

				       struct nested_vmx_msrs *msrs)

{

	msrs->exit_ctls_low =

		VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;
@@ -6815,8 +6791,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 


	/* We support free control of debug control saving. */

	msrs->exit_ctls_low &= ~VM_EXIT_SAVE_DEBUG_CONTROLS;

}



	/* entry controls */

static void nested_vmx_setup_entry_ctls(struct vmcs_config *vmcs_conf,

					struct nested_vmx_msrs *msrs)

{

	msrs->entry_ctls_low =

		VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR;
@@ -6832,8 +6811,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 


	/* We support free control of debug control loading. */

	msrs->entry_ctls_low &= ~VM_ENTRY_LOAD_DEBUG_CONTROLS;

}



	/* cpu-based controls */

static void nested_vmx_setup_cpubased_ctls(struct vmcs_config *vmcs_conf,

					   struct nested_vmx_msrs *msrs)

{

	msrs->procbased_ctls_low =

		CPU_BASED_ALWAYSON_WITHOUT_TRUE_MSR;
@@ -6865,7 +6847,12 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 
	/* We support free control of CR3 access interception. */

	msrs->procbased_ctls_low &=

		~(CPU_BASED_CR3_LOAD_EXITING | CPU_BASED_CR3_STORE_EXITING);

}



static void nested_vmx_setup_secondary_ctls(u32 ept_caps,

					    struct vmcs_config *vmcs_conf,

					    struct nested_vmx_msrs *msrs)

{

	msrs->secondary_ctls_low = 0;



	msrs->secondary_ctls_high = vmcs_conf->cpu_based_2nd_exec_ctrl;
@@ -6943,8 +6930,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 


	if (enable_sgx)

		msrs->secondary_ctls_high |= SECONDARY_EXEC_ENCLS_EXITING;

}



	/* miscellaneous data */

static void nested_vmx_setup_misc_data(struct vmcs_config *vmcs_conf,

				       struct nested_vmx_msrs *msrs)

{

	msrs->misc_low = (u32)vmcs_conf->misc & VMX_MISC_SAVE_EFER_LMA;

	msrs->misc_low |=

		MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
@@ -6952,7 +6942,10 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 
		VMX_MISC_ACTIVITY_HLT |

		VMX_MISC_ACTIVITY_WAIT_SIPI;

	msrs->misc_high = 0;

}



static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)

{

	/*

	 * This MSR reports some information about VMX support. We

	 * should return information about the VMX we emulate for the
@@ -6967,7 +6960,10 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 


	if (cpu_has_vmx_basic_inout())

		msrs->basic |= VMX_BASIC_INOUT;

}



static void nested_vmx_setup_cr_fixed(struct nested_vmx_msrs *msrs)

{

	/*

	 * These MSRs specify bits which the guest must keep fixed on

	 * while L1 is in VMXON mode (in L1's root mode, or running an L2).
@@ -6984,6 +6980,51 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps) 


	if (vmx_umip_emulated())

		msrs->cr4_fixed1 |= X86_CR4_UMIP;

}



/*

 * nested_vmx_setup_ctls_msrs() sets up variables containing the values to be

 * returned for the various VMX controls MSRs when nested VMX is enabled.

 * The same values should also be used to verify that vmcs12 control fields are

 * valid during nested entry from L1 to L2.

 * Each of these control msrs has a low and high 32-bit half: A low bit is on

 * if the corresponding bit in the (32-bit) control field *must* be on, and a

 * bit in the high half is on if the corresponding bit in the control field

 * may be on. See also vmx_control_verify().

 */

void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

{

	struct nested_vmx_msrs *msrs = &vmcs_conf->nested;



	/*

	 * Note that as a general rule, the high half of the MSRs (bits in

	 * the control fields which may be 1) should be initialized by the

	 * intersection of the underlying hardware's MSR (i.e., features which

	 * can be supported) and the list of features we want to expose -

	 * because they are known to be properly supported in our code.

	 * Also, usually, the low half of the MSRs (bits which must be 1) can

	 * be set to 0, meaning that L1 may turn off any of these bits. The

	 * reason is that if one of these bits is necessary, it will appear

	 * in vmcs01 and prepare_vmcs02, when it bitwise-or's the control

	 * fields of vmcs01 and vmcs02, will turn these bits off - and

	 * nested_vmx_l1_wants_exit() will not pass related exits to L1.

	 * These rules have exceptions below.

	 */

	nested_vmx_setup_pinbased_ctls(vmcs_conf, msrs);



	nested_vmx_setup_exit_ctls(vmcs_conf, msrs);



	nested_vmx_setup_entry_ctls(vmcs_conf, msrs);



	nested_vmx_setup_cpubased_ctls(vmcs_conf, msrs);



	nested_vmx_setup_secondary_ctls(ept_caps, vmcs_conf, msrs);



	nested_vmx_setup_misc_data(vmcs_conf, msrs);



	nested_vmx_setup_basic(msrs);



	nested_vmx_setup_cr_fixed(msrs);



	msrs->vmcs_enum = nested_vmx_calc_vmcs_enum_msr();

}